Motor vehicle dashboard crossbeam

ABSTRACT

A motor vehicle dashboard crossbeam includes a tubular beam made in a single piece provided to extend between the A posts of the structure of the motor vehicle substantially in a transverse direction of the motor vehicle and means for fastening a or each end section of the beam on an A post. The fastening means includes a first and second fastening opening in the longitudinal direction, the first opening being formed through the beam. The fastening means also includes a fastening member attached on the end section, the second fastening opening being formed through the fastening member.

TECHNICAL FIELD

The present invention relates to a motor vehicle dashboard crossbeam.

BACKGROUND

A motor vehicle dashboard crossbeam may comprise a tubular beam made ina single piece provided to extend between the A posts of the structureof the motor vehicle substantially in a transverse direction of themotor vehicle and means for fastening a or each end section of the beamon an A post, the fastening means comprising a first and secondfastening opening in the longitudinal direction, the first opening beingformed through the beam.

The dashboard crossbeam is designed to extend between the front sideposts or the A post of the structure of the motor vehicle.

The dashboard crossbeam serves in particular to stiffen the structure ofthe motor vehicle and support functional equipment of the motor vehicle,such as a steering column, a heating, ventilation and air-conditioningsystem (HVAC system), a car radio, a GPS system, a passenger airbagmodule, a glove box, etc.

It is therefore desirable for the dashboard crossbeam to have asufficient stiffness and to be fastened rigidly to the A posts.

FR 2 925 009 discloses a motor vehicle dashboard crossbeam comprising abeam made in a single piece whereof each end section is partiallycrushed to form two fastening bracket framing the end section, afastening opening being formed through each bracket.

Nevertheless, in certain situations, such a beam does not make itpossible to obtain sufficient stiffness of the beam itself and itsfastening to the A posts.

SUMMARY

One aim of the invention is to propose a dashboard crossbeam that mayhave a sufficient stiffness and be sufficiently rigidly fastened to thestructure of the motor vehicle.

To that end, the invention proposes a motor vehicle dashboard crossbeamof the aforementioned type, characterized in that the fastening meansalso comprise a fastening member attached on the or each end section,the second fastening opening being formed through the fastening member.

According to other embodiments, the dashboard crossbeam comprises one ormore of the following features, considered alone or according to alltechnically possible combinations:

-   -   the beam comprises a fastening bracket formed in a single piece        with the or each end section and protruding outward from the or        each end section, the first opening being formed through the        platen;    -   the fastening member is attached on the or each end section such        that the first opening and the second opening are positioned on        either side of the end section;    -   the first opening and the second opening are arranged        symmetrically on either side of the or each end section;    -   the or each bracket gives the beam a substantially P-shaped or        upside down P-shaped cross-section at the or each end section;    -   the first opening is formed through two opposite surfaces spaced        apart from the end section;    -   a reinforcing member is inserted into the end section between        the two opposite surfaces to keep them spaced apart;    -   the beam comprises a central section, the or each end section        being offset relative to the central section and connected        thereto by a recess; and    -   the central section is rectilinear.

The invention also relates to a motor vehicle comprising a dashboardcrossbeam as defined above.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and its advantages will be better understood upon readingthe following description, provided solely as an example and done inreference to the appended drawings, in which:

FIG. 1 is a front elevation view of a dashboard crossbeam according tothe invention;

FIG. 2 is an enlarged view of a region of the dashboard crossbeam ofFIG. 1;

FIG. 3 is a cross-sectional view along of FIG. 2;

FIG. 4 is a view similar to that of FIG. 2 illustrating an alternativeof the embodiments of FIGS. 1 to 3;

FIGS. 5 to 7 are views similar to those of FIGS. 1 to 3 of onealternative embodiment.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The motor vehicle dashboard crossbeam 2 of FIG. 1 is designed to befastened transversely between the front lateral posts, or “A” posts, ofthe structure of the motor vehicle.

In the rest of the description, unless otherwise specified, the terms“longitudinal,” “transverse,” “vertical,” “horizontal,” “top” and“bottom” are understood in reference to the usual system of orthogonalaxes of motor vehicles, illustrated in the figures and comprising:

a horizontal longitudinal axis X-X oriented from back to front;

a horizontal transverse axis Y-Y oriented from right to left; and

a vertical axis Z-Z oriented from bottom to top.

The crossbeam 2 in particular serves to stiffen the structure of themotor vehicle and support functional equipment of the motor vehicle,such as a steering column, a heating, ventilation and air-conditioningsystem (HVAC system), a car radio, a GPS system, a passenger airbagmodule, a glove box, etc.

The crossbeam 2 comprises a metal tubular beam 4 made in a single pieceextending substantially along the transverse axis Y-Y. The beam 4comprises two end sections 6 and a central section 8 extending betweenthe end sections 6. Each end section 6 is provided to be connected to arespective A post.

Each end section 6 is connected to the central section 8 by an upset 10toward the bottom such that each end section 6 is downwardly offsetrelative to the central section 8.

The central section 8 is tubular and has a constant cross section, forexample a circular cross section. It extends rectilinearly along thetransverse axis Y-Y. Alternatively, the central section 8 may extendalong a curved line, for example having rectilinear length portionsconnected by recesses, and/or a variable straight section.

The end sections 6 are tubular with a constant straight section andextend rectilinearly along the transverse axis Y-Y. They areoff-centered along the vertical axis Z-Z downwardly relative to thecentral section 6.

Each end section 6 is provided to be fastened to a respective A postusing a fastening element extending substantially along the longitudinalaxis X-X. To that end, the crossbeam 2 comprises fastening means 12 forfastening each end section 6 on the structure of the vehicle.

The fastening means 12 of each end section 6 comprise a first opening 14and a second opening 16 for fastening the end section 6 along thelongitudinal axis X-X. The first opening 14 and the second opening 16are spaced apart along the vertical axis Z-Z and are each provided forthe passage of a fastening element of the screw, bolt or rivet type,substantially along the longitudinal axis X-X. Fastening elements aresymbolized by mixed lines referenced 18 in FIG. 3.

According to the invention, the first opening 14 of the fastening means12 of each end section 6 is formed through the beam 4 and the fasteningmeans 12 also comprise a fastening member 20 attached on the end section6, the second opening 16 being formed through the fastening member 20.

In the embodiment of FIGS. 1 to 3, the fastening means 12 of each endsection 6 comprise a fastening bracket 24 extending along the endsection 6 and integral with the beam 4. Each bracket 24 extendsprotruding outwardly from the corresponding end section 6, substantiallyin a transverse and vertical plane. The first fastening opening 14 isformed through the bracket 24.

The fastening member 20 is fastened under the end section 6 such that itprotrudes downward from the end section 6. The fastening member 20 andthe bracket 24 frame the end section 6. In this way, the first opening14 and the second opening 16 frame the end section 6. Preferably, theyare arranged symmetrically on either side of the end section 6.

As shown in FIG. 3, the beam 4 has, at each end section 6, a b- orupside down P-shaped cross section, the body of which is defined by theend section and the leg of which is defined by the bracket 24.

More specifically, each end section 6 has a substantially semicircularright section defined by a first wall 26 in the shape of an arc ofcircle and a second substantially planar wall 28 extending on the chordof the arc of circle. The bracket 24 is formed by a third wall 30extending the second wall 28 outwardly and a fourth wall 32 returningtoward and connecting on the first wall 26. In this way, the bracket 24is made up of two thicknesses and the first opening 14 is formed throughthe two thicknesses.

As shown in FIG. 2, each bracket 24 extends along the corresponding endsection 6 and extends along the corresponding recess 10 up to thejunction with the central section 8, which makes it possible to ensurethe stiffness of the end section 6. The bracket 24 has a heightgradually decreasing from the free end of the end section to the centralsection 8.

The vertical center-to-center distance E between the first opening 12and the second opening 14 is provided to be large enough for rigidfastening of the end section 6 on the corresponding A post.

The single-piece beam 2 is obtained using a hydroforming method knownitself in which a tubular stub is positioned in a forming cavity and apressurized fluid, such as water or oil, is injected inside the stub todeform it outwardly until it is pressed against the wall of the formingcavity, having the desired outer shape for the beam 2. The hydroformingmethod may represent a first step aiming to form bracket stubs, whichare then crushed to obtain the shape illustrated in FIG. 3.

Each fastening member 20 is fastened on the corresponding end section 6using any suitable means, and for example by welding.

The combination of a single bracket integral with the beam and afastening member attached on the beam for the fastening of one or eachend section makes it possible to obtain a rigid beam and rigid fasteningof the beam. The end section may be provided with a significant verticaloffset relative to the central section while preserving significantinertia and obtaining a sufficient center-to-center distance between thefirst and second fastening openings owing to the additional fasteningmember attached on the end section. The crossbeam may also be obtainedinexpensively and with a limited number of assembly operations based onthe fact that a single attached fastening member is necessary.

As shown in FIGS. 1 to 3, each bracket 24 extends from the correspondingend section 6 in the opposite direction from the offset between the endsection 6 and the central section 8. More specifically, each end section6 is offset downwardly relative to the central section 8 and theassociated bracket 24 extends upward from the end section 6. Eachbracket 24 extends substantially in the extension of the central section8.

In one alternative illustrated in FIG. 4, the dashboard crossbeam 2differs from that of FIGS. 1 to 3 in that each bracket 24 extends fromthe corresponding end section 6 in the direction of the offset betweenthe corresponding end section 6 and the central section 8. Morespecifically, each bracket 24 extends downward from the end section 6.In that case, the fastening member 20 is fastened on the upper portionof the end section 6, such that it frames the end section 6 with thebracket 24. Each bracket 24 gives the crossbeam 2 a P-shaped crosssection at the corresponding end section.

The dashboard crossbeam 2 shown in FIGS. 5 to 7 differs from that of theembodiment of FIGS. 1 to 3 in that the end sections 6 are providedwithout bracket and in that the first fastening opening 14 of each endsection 6 is formed through that end section 6 in the same direction asthe recess between the central section 8 and the end section 6.

The fastening member 20 is fastened on the top of the end section 6.

In the illustrated example, each end section 6 has a quadrangular rightsection (FIG. 7) and comprises two opposite vertical surfaces 36 throughwhich the first opening 14 is formed. The first opening 14 is verticallyoffset, here upwardly, and the fastening member 20 is fastened on theend section 6 of the opposite side, here below, so as to obtain asufficient center-to-center distance E between the first opening 14 andthe second opening 16.

Each end section 6 is connected to the central section 8 by atransitional section 38 with a straight cross-section varyingmonotonously from the right cross-section of the central section 8,which is for example circular, to the right cross-section of the endsection, which is for example quadrangular.

In the illustrated example, each end section 6 extends transverselywhile being offset downwardly relative to the central section 8. Eachtransitional section 38 widens gradually downward.

This beam may be obtained by hydroforming, or by stamping throughsuccessive steps from a tubular stub having the transverse cross-sectionof the central section, the end sections being deformed throughsuccessive steps during which an inner support is inserted into the endsections and dies are applied on the outer surface of the end sectionsuntil they are given the desired straight section.

As shown in FIG. 7, the crossbeam 2 advantageously comprises areinforcing member 40 inserted inside each end section 6 and extendingbetween the vertical surfaces 36 to oppose them coming closer together.

In the illustrated example, the reinforcing member 40 assumes the formof a tubular element extending transversely between the two verticalsurfaces 36 across from the first opening 14 such that the axis of thefirst opening 14 extends through the reinforcing member 40.

The crossbeam of the embodiment of FIGS. 5 to 7 has advantages similarto those of the embodiment of FIGS. 1 to 3.

The invention is not limited to these embodiments, other alternativesbeing possible.

In particular, in the illustrated embodiments, each end section isfastened by means of a first opening provided through the beam and asecond opening provided in a fastening member attached on the endsection. Alternatively, only one of the two end sections is fastened inthis way.

1. A motor vehicle dashboard crossbeam comprising a tubular beam made ina single piece provided to extend between A posts of the structure ofthe motor vehicle substantially in a transverse direction of the motorvehicle and means for fastening a or each end section of the beam on anA post, the fastening means comprising a first and second fasteningopening in the longitudinal direction, the first opening being formedthrough the beam, characterized in that the fastening means alsocomprise a fastening member attached on the or each end section, thesecond fastening opening being formed through the fastening member. 2.The crossbeam according to claim 1, wherein the beam comprises afastening platen formed in a single piece with the or each end sectionand protruding outward from the or each end section, the first openingbeing formed through the platen.
 3. The crossbeam according to claim 2,wherein the fastening member is attached on the or each end section suchthat the first opening and the second opening are positioned on eitherside of the end section.
 4. The crossbeam according to claim 2, whereinthe first opening and the second opening are arranged symmetrically oneither side of the or each end section.
 5. The crossbeam according toclaim 2, wherein the or each platen gives the beam a substantiallyP-shaped or upside down P-shaped right cross-section at the or each endsection.
 6. The crossbeam according to claim 1, wherein the firstopening is formed through two opposite surfaces spaced apart from theend section.
 7. The crossbeam according to claim 6, comprising areinforcing member inserted into the end section between the twoopposite surfaces to keep them spaced apart.
 8. The crossbeam accordingto claim 1, wherein the beam comprises a central section, the or eachend section being offset relative to the central section and connectedthereto by a recess.
 9. The crossbeam according to claim 8, wherein thecentral section is rectilinear.
 10. A motor vehicle comprising adashboard crossbeam according to claim
 1. 11. The crossbeam according toclaim 6, wherein the two opposite surfaces spaced apart from the endsection are vertical.
 12. The crossbeam according to claim 1, whereinthe or each end section has a rectangular cross section.
 13. Thecrossbeam according to claim 1, wherein the fastening member is weldedon the or each end section.
 14. A motor vehicle dashboard crossbeamcomprising a tubular beam made in a single piece provided to extendbetween A posts of the structure of the motor vehicle substantially in atransverse direction of the motor vehicle and means for fastening a oreach end section of the beam on an A post, the fastening meanscomprising a tubular end section of the beam and a separate fasteningmember integral with the end section of the beam, wherein the fasteningmeans includes a first and second fastening opening in the longitudinaldirection, the first opening being formed through the end section of thebeam, and the second fastening opening being formed through thefastening member.